Three phase measurement

[lh666]

Hello,all

I have a question about the three phase measurement. I want to measure the currents of a three phase power cable. But I am confused that is it the Grounded signal sources or floating signal sources?

Best,

[GerdW]

Hi lh666,

when you are unsure about measurements on a "power cable" you should ask a technician with good knowledge of the matter! (It may be dangerous to start with measurements on power cables!)

That being said: What kind of current sensing device do you use?

When using current transducers you usually can measure their output with a grounded signal.

[lh666]

Hi,GerdW

I am using Rogowski Coil with integrator to measure the three phase currents. But I think it may be floating signals. The outputs of the integrator are only high and common. There is no grounded for the coil sensor. is it correct? Thanks.

Best,

lh666

[GerdW]

Hi lh666,

usually it helps to read manuals of devices in use.

Can you link the manual of your coils?

- COMMON is most often used as synonym for GROUND

- If your device just provides two wires (without any additional power supply pins or similar) it's up to you to decide on grounded or floating connections…

[lh666]

Hi,GerdW

Here is a link about the coil. The integrator need a 24Vdc power supply. It only has '+' and '-' and would be floating (isolated)

-https://aimdynamics.com/product/rcs-1800_3-phase-rogowski-coil/?_ga=2.254429184.94253713.1502689831-...

-https://aimdynamics.com/product/rc-ps_rcs-power-supply/

So it means that it is hard to decide on grounded or floating connections? Thanks.

Best,

lh666

[GerdW]

Hi lh666,

as the Rogowski converter needs an additional 24V supply you could use their COM/GND as GND for the signal outputs.

(The datasheet doesn't mention anything about insulation of the outputs so I guess they are referenced to supply GND anyway.)